Coherent analyzer of frequency-phase spectrum of electric signals

ABSTRACT

The coherent analyzer of phase-frequency spectrum of electric signals comprises an oscillator electrically connected to a first input of a first electronic gate whose second input is supplied with signals being investigated. The output of the first gate is connected to a first integrating network. The coherent analyzer is further provided with a phase distributor connected to the oscillator output and a group of gates, consisting of at least two gates, the first inputs of which are connected, together with the input of the first gate, to the outputs of the phase distributor. The second inputs of the gates of said group are supplied with electric signals being investigated, and the outputs of these gates are connected to integrating networks of a group of integrating networks whose number equals to the number of these gates connected to an amplitude analyzer. The amplitude analyzer is in turn connected to the output of the first integrating network and to the outputs of the integrating networks of said group, and is so designed that one of the outputs of the coherent analyzer only shows the maximum electrical signal among the signals arriving from all the integrating networks, and the other output shows a signal corresponding to the phase of the signal being investigated.

United States Patent Goroshkov et al.

1 Dec. 25, 1373 COHERENT ANALYZER OF FREQUENCY-PHASE SPECTRUM OFELECTRIC SIGNALS Inventors: Boris Ivanovich Goroshkov, ulitsaMetallurgov, l3, korpus 2, kv. 20;

Nikolai lvanovich Kovshov, ulitsa Utkina, 45, kv. 54, both of Moscow,USSR.

Filed: .1111) 15, 1971 Appl. No.: 162,794

US. Cl 307/232, 307/233, 307/235, 328/139, 328/140 Int. Cl. H03d 13/00Field of Search 307/232, 235, 233; 328/109, 110,115-117, 135, 139, 140

Fiehrer et a1... 328/116 Reines 307/235 Kohl 328/116 X PrimaryExaniinerj.lohn Z azworsky. Attorney-Eric [-1. Waters et al.

Reaves 328/115 X [57] ABSTRACT The coherent analyzer of phase-frequencyspectrum of electric signals comprises an oscillator electricallyconnected to a first input of a first electronic gate whose second inputis supplied with signals being investigated. The output of the firstgate is connected to a first integrating network. The coherent analyzeris further provided with a phase distributor connected to the oscillatoroutput anda group of gates, consisting of at least two gates, the firstinputs of which are 'connected, together with the input of the firstgate, to the outputs of the phase distributor. The second inputs of thegates of said group are supplied with electricsignals beinginvestigated, and the outputs of these gates are connected tointegrating networks of a group of integrating networks whose numberequals to the number of these gates connected to an amplitude analyzer.The amplitude analyzer is in turn connected to the output of the firstintegrating network and to the outputs of the integrating networks ofsaid group, and is so designed that oneof the outputs of the coherentanalyzer only shows the maximum electrical signal among the signalsarriving from all the integrating networks, and the other output shows asignal corresponding to the phase of the signal being investigated.

3 Claims 4 Drawing Figures PATENTEU uacz 5x913 SHEU 1 OF 3 FIG. I

PATENTEnumzs ms SHEET 2 0F 3 F/GJ PATENTED DEC 2 5 I975 SHE] 3 BF 3SPECTRUM OF ELECTRIC SIGNALS The present invention relates to devicesfor investigating electric signals, and more particularly, to coherentanalyzers of the phase-frequency spectrum of electric signals.

Known in the art is a coherent analyzer of the phasefrequency spectrumof electric signals, comprising an oscillator electricallycoupled to afirst input of a gate, a second input of which is connected to thesource of signals being investigated and the output, to an integratingcircuit.

In the prior art analyzers the oscillator signal is compared with thesignals being investigated. The two'signals are mixed and the resultantsignal is applied to integrating R-C networks. The DC. componentdeveloped at the output of anR.C. network is a measure of the amplitudeof that frequency component in the signal being investigated to whichthe oscillator is tuned. A disadvantage of such analyzers is that themagnitude of the DC. component depends on the phase of the two mixedsignals.

The known analyzers employing L-C and R-C networks are used atrelatively high frequencies. The use of such analyzers at low andinfra-low frequencies necessitates that their design be extremelycomplicated. A further disadvantage of such analyzers is that at suchfrequencies the quality of the frequency response characteristicsmeasured by them is not sufficiently high.

The object of the present invention lies in avoiding thesedisadvantagesby providing a coherent analyzer of the phase-frequency spectrum ofelectric signals wherein the use of a multi-phase signal distributioncircuit enables the obtaining of an amplitude-vs.- frequencycharacteristic and a -phase-vs.-frequency, characteristic of the signalbeing investigated.

The object of the present invention is attained in that the coherentanalyzer of the phase-frequency spectrum, comprising an oscillatorelectrically connected to a first input of a first gate whose secondinput is supplied with a signal being investigated and the output of thefirst gate is connected to a first integrating network, in accordancewith the present invention, is provided with a phase distributorconnected to the oscillator output and at least two gates whose firstinputs, together tor, whose outputs are connected to the transistorcollectors.

It is also prcfcrable that each transistor of the pulseheight analyzerin the coherent analyzer of the phasefrequency spectrum is provided withan individual resistor which is connected between the emitter of thetransistor and the common resistor.

The invention makes it possible to simultaneously measureamplitude-vs.frequency characteristic x flw) and a phase-vs.-frequencycharacteristic d =flw) with the first input of the first gate, areconnected to mum signal among the signals arriving from all the inte-1grating networks and the other output shows a signal corresponding tothe phase of the signal being investigated.

The pulse-height analyzer utilized in the coherent analyzer of thephase-frequency spectrum of electric signals preferably employstransistors which are equal in number to the number of all integratingnetworks, the

transistors having bases which are connected to the outputs of theintegrating circuits and the transistor emitters, to a common resistorand to a phase summaof the signals being investigated and providesbetter frequency response in the region of infra-low frequencies ascompared to prior art analyzers. The invention also enables the physicaldimensions and weight of the instrument to be reduced.

The invention will be best understood from the following description ofa specific embodiment 'when read in connection with the accompanyingdrawings inwhich:

FIG. I is a schematic diagram of a coherent analyzer of thephase-frequency spectrum of electric signals, according to theinvention; I

FIG. 2 is a schematic diagram of a pulse-height analyzer utilized in thecoherent analyzer of the phasefrequency spectrum of electric signals asdescribed herein;

FIG. 3 is a schematic diagram of a phase summator utilized in thecoherent analyzer described herein; and

, FIG. 4 is a functional diagram of a phase distributor utilized in thecoherent analyzer as described herein.

The coherent analyzer of the phase-frequency spectrum of electricsignals according to the invention comprises an oscillator 1 (FIG. 1)which is connected to the input of a phase distributor 2. The outputs ofthe phase distributor 2 are connected to the inputs of gates 3, 4, 5, 6which, in the present embodiment, employ transistors. The emitters ofthe transistors 3, 4, 5, 6 are connected together and to the positiveterminal of the power supply. Resistors 7 of equal value are connectedto the collectors of the transistors 3, .4, 5, 6. The other ends of theresistors 7 are supplied with signals being investigated.

Additionally, the collectors of the transistors 3, 4, 5, 6 are connectedto integrating networks 8,- 9, 10, 11. Each integrating networks is madeup of a resistor 12 and a capacitor 13. The outputs of the integratingnetworks 8, 9, 10, 11 are connected to the inputs of a pulse-heightanalyzer 14 which is designed so that only a maximum electric signalfrom among'the signals emitted from all integrating networks 8, 9, 10,11 appears at one output of the coherent analyzer and an electric signalcorresponding to the phase of the signal being investigated appears atthe other output.

In order to obtain a better accuracy in measuring theamplitude-vs.-frequency andphase-vs-frequency characteristics of thesignal the coherent analyzer should be preferably designed with 16, 32or more outputs (phase channels) of the phase distributor 2.

Theipulse-height analyzer 14 shown in FIG. 1 comprises transistors 15,16, 17, 18, having bases which are connected to the outputs of theintegrating networks 8, 9, l0, 11. The emitters of the transistors 15,l6, 17, 18 are connected together and to a common resistor 19, the otherend of which is connected to the zero potential terminal of the powersupply. A resistor 20 isconnected to the collector of each of thetransistors 15, 16, 17, 18. The other ends of the resistors 20 are takento 3 a positive terminal of the power supply. Furthermore, thecollectors of the transistors l5, l6, 17, 18 are connected to the inputsof a phase summator 21 at the outputof which the phase-vs.-frequencycharacteristic =j(w) of the signal being investigated is measured. Theamplitude-vs.-frequency characteristic 1 flw) of the signal is measuredacross the resistor 19.

v the phase channels of the phase distributor.

The embodiments of the pulse-height analyzer 14 described above shouldbe preferably used with the phase summator 21 (FIG. 3). The phasesummator 21 employs transistors 23, 24, 25, 26, the number of which isequal to the number of the phase channels in the phase distributor 2(FIG; 1). The bases of the transistors 23, 24, 25, 26 (FIG. 3)areconnected to the collectors of the transistors 15, 16, 17, 18,respectively. The emitters of the transistors 23, 24, 25, 26 areconnected together and to the positive terminal of the power supply. Thecollector circuits of the transistors 23, 24, 25, 26 contain resistors27, 28, 29, 30 which have the ratings R, 2R, 3R, 4R, respectively. Theother ends of the resistors 27, 28, 29,30 are connected together and toa resistor 31 across which the phase-vs-frequency characteristic d)=f(w) of the signal being investigated is measured. In order to obtainfour phase channels in the present embodiment of the coherent analyzer,the phase distributor 2 should preferably employ flip-flops whoseconnection is shown in the functional diagram in FIG. 4. The countinginput of a flip-flop 32' is connected to the oscillator 1. Two outputsof the flipflop 32 control operation of flip-flops 33 and 34. Theoutputs of the flip-flops 33 and 34 are, in their turn, connected to thebases of the transistors 3, 4, 5, 6.

The coherent analyzer of the phase-frequency spectrum of electricsignals as described herein depends for its operation on a comparison ofthe frequency of the oscillator 1 (FIG. 1) with thefrequency of thesignal being investigated fed being to the input of the coherentanalyzer.

The signal being investigated is applied to the resistors 7 from whichit is directed to the collectors of the transistors 3, 4, 5, 6.

At the same time the oscillator l furnishes a signal to the phasedistributor 2 causing the phase distributor 2 to produce output signalshaving different phases 4 d; 4 (FIG. The signal being investigated ismixed with the output signals of the phase distributor 2 (FIG. 1) at thecollectors of the transistors 3, 4, 5, 6 and the resultant signals areapplied to the integrating networks 8, 9, 10, 11.

At any instant of time one of the phases as illustrated by (b 2 (FIG.5), of the signal furnished by the phase distributor 2 (FIG. 1) willcoincide with the phase of the signal being investigated, as shown inFIG. 5 where time (t) is plotted along the X- axis and the signalamplitude (x) along the Y-axis. At

that instant of time a maximum D.C. component of the signal will appearat the output of one of the integrating networks.-

The maximum D.C. component of the signal renders one of the transistorsl5, l6, 17, 18, in effect, the transistor 16, conductive'and flowsthrough this transistor and the resistors 19 to the output of thecoherent analyzer. The magnitude of this D.C. component of the signal isa measure of the amplitude value of the signal being investigated.Additionally, the maximum D.C. component of the signal will pass to thecollector of the conducting transistor 16 and from there to the phasesummator 21 which performs a discrete-to-analogue conversion of itsphase. The magnitude of the signal at the output of the phase summator21 corresponds to the phase of the signal being investigated.

The coherent analyzer of the phase-frequency spectrum of electricsignals with a pulse-height analyzer, shown in FIG. 2, operates in thesame manner as the coherent analyzer described above, except that aresistor 22 is connected in the emitter circuit of transistors 15, I6,17, 18 for improving the accuracy of measurement of. thephase-vs.-frequency characteristics (b f(w) of the signals beinginvestigated. This somewhat changes operation of the coherent analyzer.

The maximum D.C. component of the signal emitted from one of theintegrating networks 8, 9, 10, 11 is applied to the base of one of thetransistors l5, l6, 17, 18. This maximum D.C. component of the signalfails to completely cut off the other transistors, which factdistinguishes the operation of the pulse-height analyzer from that ofthe pulse-height analyzer 14 shown in' FIG. 1. The pulse height analyzer14 (FIG. 2) may be in a condition in which, apart from one fullyconducting transistor, the base of which is fed with the maximum D.C.component of the signal, two more of its transistors are conducting astheir bases are fed with D.C. components of two signals with phasesadjacent to the phase of the maximum D.C. component of the signal.

This condition is unstable. Only two transistors may conduct at any onetime and the magnitude of the signals at the outputs of thesetransistors may be used to find the intermediate phase values of thesignal being investigated. This makes it possible to pass from an abruptvariation of thephase-vs-frequency characteristic qb =flw) to a smoothvariation, which is an advantage of the present pulse-height analyzer.

It is particularly emphasized that the coherent analyzer describedherein is unique in that it offers the means for measuring thephase-vs.-frequency characteristic qb flw) of the signal beinginvestigated along with its. amplitude-vs,-frequency characteristic xflw). Moreover, the coherent analyzer enables investigation of signalsin the region of infra-low frequencies, thus considerably extending thefield of application of such analyzers.

What is claimed is:

1. A coherent analyzer of the phase-frequency spectrum of electricsignals, comprising an oscillator; a. first gate having a first inputbeing electrically connected to said oscillator, a second input of saidgate being supplied with a signal being investigated; a firstintegrating circuit connected to the first input of said first gate; aphase distributor connected to the output of said oscillator; a group ofgates, consisting of at least two gates, said gates being first inputsconnected to the outputs of said phase distributor, the first input ofthe first gate being also connected to the output of said phase .dis-

tributor, said gates having second inputs supplied with a signal beinginvestigated; a group of integrating networks, the number of whichequals to the number of said gates of said group of gates, said networksbeing connected to the outputs of said gates; and amplitude analyzerconnected to the output of said first integrating circuit and to theoutputs of said integrating networks of said group of integratingnetworks, said amplitude analyzer being adapted so that upon one of theoutputs of the coherent analyzer showing only the maximum electricsignal among the signals arriving from said first integrating networkand said group of integrating networks, the other output shows anelectric signal corresponding to the phase of the signal beinginvestigated, and means to supply electrical power to said first gateand said group of gates, and said amplitude analyzer.

2. A coherent analyzer as claimed in claim 1, said amplitude analyzercomprising transistors equal in the emitter of said transistor and saidcommon resistor.

1. A coherent analyzer of the phase-frequency spectrum of electricsignals, comprising an oscillator; a first gate having a first inputbeing electrically connected to said oscillator, a second input of saidgate being supplied with a signal being investigated; a firstintegrating circuit connected to the first input of said first gate; aphase distributor connected to the output of said oscillator; a group ofgates, consisting of at least two gates, said gates being first inputsconnected to the outputs of said phase distributor, the first input ofthe first gate being also connected to the output of said phasedistriButor, said gates having second inputs supplied with a signalbeing investigated; a group of integrating networks, the number of whichequals to the number of said gates of said group of gates, said networksbeing connected to the outputs of said gates; and amplitude analyzerconnected to the output of said first integrating circuit and to theoutputs of said integrating networks of said group of integratingnetworks, said amplitude analyzer being adapted so that upon one of theoutputs of the coherent analyzer showing only the maximum electricsignal among the signals arriving from said first integrating networkand said group of integrating networks, the other output shows anelectric signal corresponding to the phase of the signal beinginvestigated, and means to supply electrical power to said first gateand said group of gates, and said amplitude analyzer.
 2. A coherentanalyzer as claimed in claim 1, said amplitude analyzer comprisingtransistors equal in number to the number of all of said integratingnetworks, the bases of said transistors being connected to the outputsof said integrating networks and the emitters of said transistors beingelectrically connected to a common resistor, and a phase summator havinginputs connected to the collectors of said transistors.
 3. A coherentanalyzer as claimed in claim 2, each of said transistors of saidamplitude analyzer being provided with an individual resistor connectedbetween the emitter of said transistor and said common resistor.